---
title: mass
framework: realitykit
role: symbol
role_heading: Instance Property
path: realitykit/physicsmassproperties/mass
---

# mass

The mass in kilograms.

## Declaration

```swift
var mass: Float
```

## Discussion

Discussion For a mass of 0 or infinity, the simulation treats the object as PhysicsBodyMode.kinematic. That is, the object doesn’t respond to forces.

## See Also

### Getting mass properties

- [inertia](realitykit/physicsmassproperties/inertia.md)
- [centerOfMass](realitykit/physicsmassproperties/centerofmass.md)